Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

A decline portal, right, stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

A decline portal, right, stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

William 'Bill' Marmion, Western Australia's minister for mines and petroleum, speaks during the opening ceremony of Rio Tinto Group underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

William 'Bill' Marmion, Western Australia's minister for mines and petroleum, speaks during the opening ceremony of Rio Tinto Group underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

William 'Bill' Marmion, Western Australia's minister for mines and petroleum, speaks during the opening ceremony of Rio Tinto Group's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

William 'Bill' Marmion, Western Australia's minister for mines and petroleum, speaks during the opening ceremony of Rio Tinto Group's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Representatives from the Mirriuwung and Gidja people, the traditional owners of the land, perform a Manthe ceremony with Rio Tinto Group employees during the opening of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, right, shakes hands with representatives from the Mirriuwung and Gidja people, the traditional owners of the land, during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, right, shakes hands with representatives from the Mirriuwung and Gidja people, the traditional owners of the land, during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Mining benches stand at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Mining benches stand at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Machinery stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Machinery stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Machinery stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Machinery stands at the Rio Tinto Group Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images

Alan Davies, chief executive officer of diamonds and minerals at Rio... News PhotoAsia,Australasia,Australia,Australian Culture,Business,CEO,Ceremony,Corporate Business,Delivering,Diamond - Gemstone,Finance,Gemstone,Growth,Horizontal,Kununurra,Man Made Object,Mine,Miner,Mineral,Mining,Oceania,Opening Ceremony,Photograph,Precious Gem,Rio Tinto Group,StandingPhotographer BloombergCollection: Bloomberg 2013 BloombergAlan Davies, chief executive officer of diamonds and minerals at Rio Tinto Group, stands for a photograph during the opening ceremony of the company's underground expansion of the Argyle diamond mine in Kimberley, Australia, on Tuesday, April 30, 2013. Production at Argyle, which supplies more than 90 percent of the world’s pink diamonds, will rise to 20 million carats annually as production moves underground, while costs will fall. Photographer: Ian Waldie/Bloomberg via Getty Images